JPH10302741A - Nonaqueous electrolytic secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolytic secondary battery allowing the application of reflow soldering by using polyphenylene sulfide resin for a gasket laid between a negative electrode can and a positive electrode can, regarding a nonaqueous electrolytic secondary battery having a negative electrode made of alloy mainly composed of lithium and tin, and a positive electrode formed out of lithium manganese oxide expressed by a specific composition formula. SOLUTION: Regarding this nonaqueous electrolytic secondary battery element, a positive electrode 5 is formed out of Lix MnOy containing a conductive agent and a binding agent, a negative electrode 2 is formed out of Li-Sn alloy containing a conductive agent and a binding agent, and an electrolyte is composed of perchloric lithium dissolved in propylene carbonate. Also, a separator 4 is formed out of the nonwoven fabric of glass fiber containing an organic binder. A gasket 3 is prepared by injection molding a straight chain PPS resin containing glass fiber mainly composed of SiO2 , at resin fusing temperature, and formed to a prescribed shape. According to this construction, the battery allows the application of reflow solder involving high temperature environment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous electrolyte secondary battery using a non-aqueous electrolyte having lithium ion conductivity as a negative electrode active material using a material capable of inserting and extracting lithium ions. In gasket materials.

[0002]

2. Description of the Related Art Conventionally, button-type or coin-type organic electrolyte batteries using, for example, a polypropylene resin as a gasket have been widely used in portable electronic devices and communication devices in recent years, because of their high energy density and economical efficiency. It is used as a backup power supply. Recently, reflow soldering (soldering in a high-temperature atmosphere, for example, 180 to 240 ° C.) can be mounted on a circuit board including this type of battery, and the battery performance is maintained even after being exposed to such a high-temperature environment. There is a strong demand for what can be done.

[0003] In order to satisfy these demands, gaskets, which are one of the constituent materials of batteries, have been particularly improved, but not sufficiently. Here, FIG. 1 shows a configuration example of a conventional button type secondary battery (diameter 6.8 mm, thickness 2.1 mm) of this type. In the figure, 1 is a negative electrode can made of stainless steel, 2
Is a negative electrode mainly composed of lithium (Li) and tin (Sn),
Reference numeral 3 denotes a gasket made of propylene resin, 4 denotes a separator made of glass fiber, 5 denotes a positive electrode mainly composed of LixMnOy, 6 denotes a positive electrode can made of stainless steel, and a solute of 0.5 in propylene carbonate as a solvent.
What melt | dissolved mol / l lithium perchlorate was used.

[0004] Usually, polypropylene resins have been used for gaskets of button-type and coin-type batteries because of their excellent thermal stability (melting point: 164 to 170 ° C), mechanical strength and chemical resistance. The gasket is arranged to have a function of insulating the positive electrode can and the negative electrode can, preventing leakage from the inside of the battery, and preventing intrusion of moisture from the outside (in the atmosphere). However, in a high-temperature environment (the above-described reflow soldering conditions), the gasket melts, so that a gap is created in the contact surface between the gasket and the positive electrode can and the negative electrode can, causing liquid leakage, and furthermore, the negative electrode attached to the gasket. The battery is significantly damaged due to the detachment of the can.

[0005]

As described above, a conventional battery is used in a high-temperature environment, for example, by reflow soldering (for example, 1).
(Atmosphere of 80 ° C. for 5 minutes and 240 ° C. for 10 seconds) to melt the polypropylene as a gasket material to generate liquid leakage and to scatter the liquid to adhere to other electronic components mounted on a circuit board, for example. Function is also impaired. The present invention solves the above-mentioned problems, and an object of the present invention is to provide a non-aqueous electrolyte secondary battery capable of reflow soldering.

[0006]

In order to achieve this object, the present invention provides a non-aqueous electrolyte battery comprising a negative electrode composed of an alloy mainly composed of Li and Sn and a positive electrode represented by a composition formula of Li _x MnO _y. , A linear polyphenylene sulfide (PPS) resin to which glass fiber or a thermoplastic elastomer is added is used as a gasket interposed between the positive electrode can and the negative electrode can.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS With the above-described structure, the present invention can provide a battery which prevents liquid leakage and breakage in a high-temperature environment of reflow solder and further improves reliability.

[0008]

An embodiment of the present invention will be described with reference to FIG. (Example 1) The positive electrode was Li _x Mn containing a conductive agent and a binder.
O _y , the negative electrode is a Li-Sn alloy containing a conductive agent and a binder, and the electrolyte is propylene carbonate in lithium perchlorate 0.5.
mol / l dissolved, the separator is a glass fiber nonwoven fabric containing an organic binder, and the above elements are the same as those of the conventional battery. Hereinafter, the gasket 3 of the present invention contains 30% by weight of glass fiber mainly composed of SiO _2. The linear PPS resin thus obtained was injection-molded at a cylinder temperature of 340 ° C. (resin melting temperature) to obtain a predetermined shape, and a battery as shown in FIG. 1 was assembled.

(Example 2) A gasket is the same as Example 1 except that a linear PPS resin containing 20% by weight of a polyolefin-based thermoplastic elastomer is injection-molded at a cylinder temperature of 320 ° C. (Comparative Example) The gasket was the same as Example 1 except that a polypropylene resin was injection-molded at a cylinder temperature of 210 ° C.

[0010] The glass fibers contained in the linear PPS resin have improved mechanical strength, increased heat deformation temperature,
Contributes to improvement of dimensional stability, preferably 5 to 50% by weight,
The optimum is from 10 to 40% by weight. The content of the elastomer is preferably 5 to 30% by weight, and if it is outside this range, hardening and cracking occur, and plastic deformation occurs particularly at high temperatures. The optimum is between 10 and 25% by weight. When the content of the above-mentioned glass fiber or thermoplastic elastomer is out of the above range, the fluidity of the resin at the time of injection molding deteriorates, which is not suitable for mass production, and further generates burrs, which is a problem in battery assembly. The batteries of Examples 1 and 2 and Comparative Example were evaluated by a high-temperature storage test because their heat resistance is the easiest identification method based on the change in appearance due to heating. The results are shown in Tables 1 to 3. The high-temperature storage time was 160 minutes at 180 ° C. and 180 minutes at 240 ° C.
Then, it was set to 10 seconds.

Table 1 shows the results of visual determination of discoloration and deformation of the gasket. Table 2 shows gaskets and positive. It is the result of observing the presence or absence of liquid leakage from the gap of the negative electrode can with a microscope of 20 times.

[0012]

[Table 1]

[0013]

[Table 2] Tables 1 and 2 show that the linear PPS resins of Examples 1 and 2 used as gaskets showed only a slight change in appearance under a high-temperature environment, and further showed no leakage. It showed heat resistance. On the other hand, the polypropylene resin of the comparative example is deformed by melting at 160 ° C. and 180 ° C., causing liquid leakage. did.

Table 3 shows the measurement results of the open circuit voltage (Eo) and the internal resistance (Ri) after storage at a high temperature.

[Table 3] From Table 3, Examples 1 and 2 show that E
Although the change between o and Ri is slight, in the comparative example, at 160 ° C. and 180 ° C., the decrease in Eo and the rise in Ri were remarkable, and the battery performance was deteriorated. When stored at 240 ° C., the battery was damaged and Eo and Ri could not be measured. I didn't. The above results show that the gasket made of the linear PPS resin of the present invention is superior to the gasket made of the conventional polypropylene.

As described in detail above, the linear type PPS resin containing glass fiber or thermoplastic elastomer has high fluidity and excellent dimensional stability, so that a gasket can be formed with high precision, and the gasket has a mechanical property. Of course, since heat resistance is particularly excellent when the heat distortion temperature is 260 ° C. or more, it is most suitable for a gasket for a battery which requires high temperature resistance.

[0016]

As is apparent from the above description, the nonaqueous electrolyte battery of the present invention has an effect that it can be used for reflow soldering in a high-temperature environment, and its industrial value is great.

[Brief description of the drawings]

FIG. 1 is a configuration sectional view of a button type battery.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Negative electrode can 2 Negative electrode 3 Gasket 4 Separator 5 Positive electrode 6 Positive electrode can

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ Identification code FI C08L 23:00) (72) Inventor Tsugio Sakai 1-8-8 Nakase, Mihama-ku, Chiba-shi, Chiba 72) Inventor Kensuke Tahara 1-8-8 Nakase, Mihama-ku, Chiba-shi, Chiba Seiko Electronic Industry Co., Ltd.

Claims (2)

[Claims] 1. A non-aqueous electrolyte battery comprising a negative electrode made of an alloy mainly composed of lithium and tin and a positive electrode made of a lithium-containing manganese oxide represented by a composition formula LixMnOy,
A non-aqueous electrolyte secondary battery using a polyphenylene sulfide resin as a gasket interposed between a negative electrode can and a positive electrode can. 2. The non-aqueous electrolyte secondary battery according to claim 1, wherein the gasket contains a glass fiber or a thermoplastic elastomer in a linear polyphenylene sulfide resin.